Engine Diesels, Runs After Shutoff

ENGINE DIESELS

Description
After turning the Ignition switch to "OFF", the engine continues to run for several seconds.

Explanation
After the ignition is turned off, a combination of compression and heat continues to ignite the air/fuel mixture and temporarily maintain combustion.

NOTE: Fuel delivery is dependent upon air flow through the carburetor. As long as the engine continues to rotate, an air/fuel mixture will be delivered to the pistons.

Causes

High Idle Speed
High idle speed at the time of ignition shutoff provides sufficient momentum to continue rotating the crankshaft. If cylinder temperatures are sufficiently hot, the incoming fuel mixture will ignite and the engine will continue to diesel.

Testing
- Check idle speed and adjust as necessary.
- Check cooling system operation. See Cooling System. Cooling System